Engines



T H DUFF May 7, 1968 ENGINES 7 Sheets-Sheet 2 Filed April l2, 1966 INVENTOR T Duff BY www wfms May 7, 1968 T H DUFF 3,381,671

ENGINES Filed April 12, 1966 '7 Sheets-Sheet 3 May 7, 1968 ENGINES '7 Sheets-Sheet 5 Filed April l2, 1966 T H D u ff INVENTOR WM Wfm ENGINES Filed April 12, 196e 7 Sheets-Sheet 7 seo' sov

INVENTOR 4T H Duff BY f Wmfms United States Patent Oiiice 3,381,671 Patented May 7, 1968 3,381,671 ENGINES T H Duif, 1003 Santa Monica St., San Antonio, Tex. '78201 Fixed Apr. 12, 1966, ser. No. 542,034 15 Claims. (Cl. 12S- 45) ABSTRACT F THE DISCLOSURE An engine' having opposed cylinders aligned along a common axis and pistons disposed therein and interconnected by a centrally positioned assembly including a cam engageable with cam surfaces in the engine body for rotating the pistons and central connecting assembly as a unit as the pistons reciprocate in the cylinders. Power transfer from the central connecting assembly is provided by gear teeth along the cam meshing with gears supported by the engine housing for transferring power from the reciprocating rotating central assembly to rotatable gears supported by the engine housing. Ports in the cylinder wall and pistons skirt are aligned during the reciprocating rotation of the pistons for fuel intake and exhaust. In one form of the engine fuel is drawn into each cylinder beneath the piston therein, compressed on the power stroke, and transferred into the combustion chamber. Another form of the engine has a central fuel chamber provided in each piston communicating with the combustion chamber into which one portion of a fuel charge is transferred through a series of chambers within the piston while another portion of the fuel charge, generally the air, is drawn into and transferred from beneath the piston into the combustion chamber independently of the fuel charge portion in the central chamber at the piston.

This invention relates to power conversion apparatus and more particularly to internal combustion engines.

It is one object of the invention to provide a new and improved power conversion apparatus.

It is another object of the invention to provide a new and improved engine.

It is a particularly important object of the invention to provide a new and improved internal combustion engine.

It is another object of the invention to provide a new and improved cam type engine.

It is a further object of the invention to provide a cam type engine of the two cycle form.

It is a still further object of the invention to provide an internal com-bustion engine wherein opposed pistons on connecting rods extending along a common axis coincident with the long itudinal axes of the pistons drives a centrally positioned rotary cam having cam surfaces causing the cam to rotate as it reciprocates to effect rotation of the pistons and their connecting rods and having gear teeth to transmit power to one or more gear wheels.

It is another object of the invention to provide a cam type engine having opposed cylinders aligned along a common axis and adapted to reciprocate a centrally positioned rotary cam having cam surfaces engageable with fixed rollers effecting rotational motion of the cam and the pistons coincident with their reciprocating motion to deliver power to gear means meshing with gear teeth around the cam and to effect valving action between the rotating pistons and their fixed cylinders.

It is another object of the invention to provide an internal combustion engine having opposed cylinders aligned along a common axis and connected with piston rods each having an axis coincident with the common axis of the pistons and being adapted to reciprocate along such coincident axis thereby eliminating lateral or side lforces in both the piston rods and between the pistons and their cylinders.

It is another object of the invention to provide a two cycle internal combustion engine in which a localized stratified fuel charge is delivered into one section of each combustion chamber of the engine while an air charge is delivered into another section of the combustion charnberto provide an oxygen supply for improving the combustion characteristic of the fuel in the chamber.

It is a further object of the invention to provide an internal combustion engine wherein a first charge of fuel isV delivered into a central section of each piston of the engine while a separate second charge of fuel is cornpressed in a generally annular section of the combustion chamber around the portion' of the chamber containing the fuel charge so that when the fuel charge is ignited it burns radially outwardly toward the cylinder head of each cylinder thus providing smooth operation and extending the burning time of each ignition or combustion cycle.

It a still further object of thel invention to provide an internal combustion engine in which the opening and closing of inlet and outlet ports both for fuel and exhaust of combustion products are controlled by combined longitudinal and rotational motion of each piston within its cylinder.

It is another object of the invention to provide an engine having longitudinally reciproca-ble pistons rotatable about their longitudinal axes and having base end edges of predetermined contour for covering and uncovering cylinder wall ports to effect valving action.

It is another object of the invention to provide an engine wherein the space within its primary piston is niinimized to reduce the travel time of the fuel charge in its transfer from beneath the piston to the combustion charnber.

It is a further object of the invention to provide an engine having cylinder chamber configuration and port arrangements which improves the cooling beneath the piston.

It is another object of the invention to provide an engine wherein load bearing parts, such as cams and rollers, are located remotely from high heat areas of the engine.

It is a still further object of the invention to provide an engine having flexibility in its cam design and port configuration and positioning which permits optimum adaptation to the burning characteristics of different fuels Iby control of engine operating characteristics including the point of maximum acceleration of the piston.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

FIGURES 1 `and l-A taken together constitute a sectional lView throng-h a two cycle cam type 'internal combustion engine embodying the invention and showing one piston in FIGURE 1 at the top of its stroke ready to begin its power stroke and a piston in FIGURE l-A at the end of its power stroke ready to begin its compression stroke;

FIGURE 2 is a view in section taken along the line 2-2 of FIGURE 1;

FIGURE 3 is an exploded longitudinal view in section of one piston assembly of the engine of FIGURES 1 and 1-A;

FIGURE 4 is an exploded fragmentary planar development of the 36.0 degrees of surface on portions of the secondary piston rod, the secondary cylinder sleeve, and the pri-mary piston rod of the piston assembly of FIGURE 3 showing their dual fuel charge transfer ports;

FIGURES 5 and 5-A taken together constitute a sectional view of la modified form of internal combustion engine embodying the invention showing a piston in FIG- URE 5 at the beginning of its power stroke and a piston 3 in FIGURE 5-A at the beginning of its outward stroke to complete scavenging and accomplish compression;

FIGURE 6 is a fragmentary partially exploded planar development of the 360 degrees of surface of the inside of the cylinder, the outside of the piston, and the outside of the cam of the engines shown in both FIGURES 1 and l-A and FIGURES 5 `and S-A.

FIGURE 7 is a fragmentary view in section along the line 7-7 of FIGURES l-A and S-A illustating a fuel transfer flow passage formed in the cylinder wallof each engine connecting inner and outer transfer ports for introducing a fuel charge into lthe combustion chamber of a cylinder from its intake chamber; and

FIGURE 8 is a reduced fragmentary exploded view in perspective illustrating one cam guide and gear assembly showing a gear wheel and its support members for holding the gear in rotatable meshing relationship with the cam.

Referring to the drawings, particularly FIGURES 1 and l-A, a two-cylinder, two-cycle, internal combustion engine 20 embodying the invention includes 4a crankcase or cam and bearing box 21 secured on a suitable base, not shown, opposed first and second or right iand left cylinders A and B with their piston assemblies C and D, respectively, a cam E within the crankcase interconnected between the piston assemblies, and identical gear and cam guide assemblies F and G supported in 180 degree spaced relationship on opposite sides of the crankcase. The pistons are secured to the cam in 90 degree spaced phase relationship so that they reciprocate simultaneously with each other and the cam, one piston moving through a power stroke while `the other is in its compression stroke. As thecam is reciprocated with-in the crankcase, a set of guide rollers 30 yand 31 of each cam guide assembly engage end cam surfaces 32 and 33, respectively, guiding the cam and thus causing it to rotate .as it reciprocates and effecting corresponding rotation of the pistons as they re-` ciprocate. As the cam rotates and reciprocates, its motion is transferred into single rotary `motion andy power is transmitted from the cam through the two gear wheels 34, each of which meshes with external gear teeth 35 formed around the outside surface of the cam ina continuous pattern corresponding with the cam surfaces 32 and 33 so that the cam may reciprocate while remaining meshed with the gear wheels 34. The gear wheels are engaged with Whatever apparatus, not shown, is driven by the engine.

The cylinder assemblies A and B, thepiston assemblies C and D, and the gear and cam guide assemblies F and G, are, respectively, identical assemblies and thus identical reference numerals shall be used to identify their component parts.

As illustrated in FIGURE 1, the first cylinder assembly A includes a cylinder 22 secured on the crankcase 21 by a plurality of bolts 40 which are threaded through flanges or lugs 41 on the cylinder into similar lugs on the crankcase. The bolts 40 extend through lug protrusions 41a on a manifold unit 42 which is clamped between the cylinder and the crankcase providing both a base end closure 431between the crankcase and the cylinder and inlet flow passages 44 for introduction of fuel into the cylinder. The Imanifold provides a fuel inlet chamber 45 at the base end of the cylinder in which are a plurality of circumferentially spaced radial vanes 50 which v-ary in `size and degree of curvature of their surfaces as 'best seen in FIG- URE 2 to facilitate distribution of incoming fuel. A' base end section 51 of the cylinder 22 fits within an opening 52 in the outer face of the manifold and t-he cylinder is seated on an external annular ange 53 which engages the outer surface of the manifold as shown `in FIGURE l.

Air -inlet conduits 54 are formed integral with the cyllinder providing air inlet ilow passages 55 which conduct air into the cylinder through two ports 60` opening through the inside wall of the cylinder spaced circumferentially 180 degrees apart. Two exhaust conduits 61 formed integral with the cylinder at 180 degrees circumferential spacing each provide lan exhaust flow passage 62 which opens to the inside cylinder wall through an exhaust port 63. As illustrated in FIGURE 6, which shows a planar development of the inside surface 64 of the cylinder 22, ltiheair inlet ports 60 having an irregular configuration the function of which will be explained hereinafter and the exhaust ports 63 are slotted or formed of three vertical oriented sections collectively rforming a generally circular opening. Spaced around the cylinder about 90 degrees removed from each set of inlet and exhaust ports and spaced from each other 180 degrees are two sets of outer and inner transfer ports 65 and 70, respectively. The outer and inner transfer ports are aligned with each other longitudinally. As shown in FIGURE 7, the outer and inner transfer ports open into a transfer ow channel 71 formed in each cylinder wall for conducting air from an intake chamber 71a of the cylinder around the piston head into a combustion chamber 7117 of the cylinder when the piston skirt is aligned to uncover the inner transfer ports in the cylinder. f f

The -cylinder 22 is provided with a plurality of integral parallel spaced external annular ns `69 around its side wall and parallel spaced head fins 72 extending from its head 73 to aid in air cooling the cylinder walls by providing a maximum amout of surface area to expedite heat conduction from the cylinder. A spark plug 74 is secured through a fitting 75 threaded into the head 73 of the cylinder.

The piston assembly C is illustrated in FIGURE 1 at the beginning of its power stroke, that is, the position of the piston when the fuel mixture within the combustion chamber of the cylinder `is ignited and' starts driving the piston inwardly away from its cylinder head. The piston assembly C is shown disassembled in FIGURE 3, while FIGURE 4 is a planar development of the various piston assembly surfaces having Ifuel and air ports for transfer of fuel and air charges into the combustion chamber of each cylinder. The piston assembly C includes a primary piston having a partially hollow tubular piston rod 81, a secondary annular cylinder 82 having an outer wall section 82a and a tubular inner wall or sleeve section 82b through which the piston rod 81 slidably fits, and a secing a tubular piston rod S4 which telescopically slides over ondary piston SSf-fitting in the secondary cylinder and havthe tubular section 8217.

The primary Ipiston 80 has a tubular skirt 85 which extends from its head and has an irregular base end edge surface 91 so contoured that as the pistony reciprocates and simultaneously rotates its skirt selectively covers and uncovers the air inlet ports 60` for admitting air into the primary piston as will be explained in more detail later. The piston skirt 85, shown in planar development inFIGURE 6, is also provided with a pair of transfer windows 92 circumferentially spaced around the piston 180 degrees apart and longitudinally positioned in the piston to coincide with the lower transfer ports 70 during the spiral movement of the piston for releasing air from within the piston skirt into the lower transfer ports for transferring air entering the cylinder through the intake ports 60 into the combustion chamber through the transfer ow passage.

A Iplurality of external annular piston ring grooves 93 are formed in the piston near its head to receive piston rings, not shown, for sealing between the piston and the cylinder wall surface 64. The piston head 90 includes an external annular protuberance 94 which connects with a tubular head end section 95 of the piston rod. As the piston completes its compression and begins its power stroke, as in FIGURE l, the protuberance 94 is positioned in close spaced relationship with the piston head 73 to momentarily define a substantially separate annular chamber 71e` in the combustion chamber in which a separate fuel charge, -generally an air charge, is compressed, as explained hereinafter in more detail. The tubular end section 95 of the piston rod defines an annular chamber 100 Within the piston skirt around the piston rod and a central tubular cham-ber 101 extending through the piston along its longitudinal axis and opening through its head end 90 through the protuberance 94.

The primary piston rod 81 includes the hollow tubular head end section 95, an intermediate or central section 102, and a reduced, preferably solid, stem or base end 1 section 10'3 which connects the piston rod with the cam E.

The intermediate section 102 is either partially lilled, as illustrated, with a light metal 102:1 or is sealed internally in any satisfactory manner providing a surface 103 to define an inward end of an internal chamber 1104 extending into a protuberance 105 formed on the head end of the central section 102 extending into the chamber 101. A pair of elongate ports 110 spaced circumferentially 180 degrees from each other are provided in the central section 102 and its protuberance. A pair of rectangular ports 111 are provided in the section 95 of the piston rod spaced 180 degrees from each other and 90 degrees from the ports 110 between the base end of the protuberance 105 and the head end of the piston opening into the central chamber 101 of the primary piston.

The secondary cylinder 82 has an external annular fbase flange 1112 which is clamped as shown in FIGURE 1 between the base end section 51 of the cylinder 22 and the free ends or edges of the vanes 50 so that the secondary cylinder is held stationary within the base end section of the cylinder. The outer wall section 82a and the sleeve section 8211 define an annular chamber 114 Within the secondary cylinder to receive the annular piston 83 when the piston assembly is assembled as in FIGURE 1. The secondary cylinder has a head 115 and an axially extending flange or annular protuberance 116 which functions as a continuance of the sleeve 82b and is received within the protuberance 94 when the primary piston and secondary cylinder are telescoped together at the end of the power stroke of the primary piston as illustrated by the piston assembly D in FIGURE l-A. The sleeve 82h of the secondary cylinder has a pair of elongate irregular shaped longitudinal ports 120 circumferentially spaced 180 degrees around the sleeve Ifor admitting a fuel charge into the annular chamber 114 above the secondary piston 83 and allowing such charge to be discharged from the chamber as will be explained in detail hereinafter.

The secondary tubular piston rod 84 of the secondary piston its in telescopic slidable relationship over the sleeve 8217 and is provided with a pair of rectangular longitudinal ports 121 spaced 180 degrees circumferentially around the piston rod to cooperate with the slots 120 in the transfer of a fuel charge through the piston assembly as explained hereinafter. The secondary piston 83 has a plurality of external annular piston ring grooves 122 each of which receives a piston ring, not shown, for sealing around the piston within the secondary cylinder 82. The 'base end of the secondary piston rod 84 has an internal annular ange 123 defining a central opening 124 to receive the stem section 103 of the primary piston rod 81. The flange 123 has locking pin holes 125 each of which receives a locking pin 130 to hold the secondary piston rod and piston against rotation relative to the primary piston rod and piston when the pistons `are assembled together as shown in FIGURE 1.

The secondary cylinder 82, as previously noted, is secured at a xed position within the cylinder 22 by clamping the end ange 112 between the vanes v50 and the section 51 of the cylinder 22. The primary piston 80 telescopes over the secondary cylinder with primary piston rod 81 extending in slidable relationship through the sleeve 82b of the secondary cylinder. The secondary piston rod 8-4 telescopes over the sleeve 82b with the secondary piston 83 received Within the annular chamber 114 of the secondary cylinder. The end flange 123 of the secondary piston rod 84 iits around the stem 103 on the primary piston rod -81 with the lock pins 130 extending through the holes in the flange 123 into blind lock pin holes 131 in the end 132 of the primary piston rod to hold the secondary piston rod against rotation relative to the primary piston rod. Two nuts 133 are threaded on the stem 103 to secure the flange 123 on the stem against the end 132 of the primary piston rod. Thus, the primary piston rod 81 fits through the sleeve 82b while the secondary piston rod 84 fits over the sleeve '82b. The primary and secondary pistons and their piston rods are therefore movable as a unit with the primary piston reciprocating and rotating within the 'cylinder 22 and the secondary piston reciprocating and rotating within the fixed secondary cylinder 82. The secondary piston moves into the secondary cylinder until it closely approaches but does not actually contact the cylinder head 115. The relationship of the ports 110, 111, and i121 to each other remain fixed while these ports reciprocate and rotate relative to the ports 120 in the sleeve SZb.

The right piston assembly C and the left piston assembly D are both connected by their stems 103 to the centrally positioned cam E in the crankcase 21 so that the cam reciprocates with the pistons while the cam is guided by the rollers 30 and 31 engaging the cam surfaces 32 and 33, respectively, forcing the cam and the piston assemblies C and D to rotate. The cam serves a multiple function of interconnecting the piston assembles C and D, as a cam for effecting rotation of the piston assemblies, and as a gear wheel to transmit power to the gears 34.

The cam E is preferably a symmetrical unitary structure or integral unit comprising a pair of axially extending wing or end sections 134 and an oppositely extending pair of identical axial wing or end sections 135. The planar development of the cam E in FIGURE 6 shows that the two wings 134 are spaced 180 degrees from each other, the wings 135 are spaced 180 degrees from each other, and the wings 134 are spaced 90 degrees from the wings 135 so that the wings 134 and 135 alternate each 90 degrees around the cam. The identical, reciprocal, end cam surfaces 32 and 33 are continuous edge surfaces of the adjoining wing sections of the cam. The outer annular surface of the cam is provided with the gear teeth 35 which extend axially and are longitudinally misaligned from each other sufliciently to follow the exterior surface of the cam. As the cam rotates the cam surfaces 32. and 33 move between the pairs of rollers 30 and 31 forcing the cam to reciprocate one stroke each 90 degrees of cam rotation. The cam moves from the position shown in FIGURE 1 to the other end of its stroke and back to the position of FIGURE 1 each 180 degrees of its rotation.

The cam E has an inwardly extending lug formed within each of its wings 134 and an identical inwardly extending lug 141 formed within each of its wings 135 for connection of the piston assemblies C and D to the cam. The connecting of each of the primary piston rods to the cam is best understood by reference to FIGURE 1-A which s'h-ows a side view in section of the connection between the primary piston r-od 81 of the piston assembly D with the cam wings 135. The spindle 103 of the piston rod 81 is secured to a plate 142 which is connected to assirl the lugs 141 by threadcd bolts 143. The inwardly tapered free end section 103a of the stem 1t3s received within a correspondingly tapered bore 144 through the plate 142. The stem is held in the bore 144 by a nut 145 threaded on its free end. A locking key is positioned within corresponding longitudinal recesses 15tfa in the spindle 103 `and in the plate 142 to hold the spindle against rotation relative to the plate so that rotation of the cam rotates the piston assembly D. The right piston assembly E is secured by its piston rod S1 with the other end of the cam to the lugs 140 on the cam wings 134. The spindle 103 is received within a tapered bore 151 through a plate 152 which is secured between the cam wing lugs 140 by threaded bolts, not shown, identical to the bolts 1-43. Also, the spindle is locked against rotation relative to the plate by a key 150, not shown, inserted between the spindle and the plate as previously described. The spindle 103 which is tapered toward its free end is secured to the plate 152 by a nut 153 threaded on the free end of the spindle.

The pair of gears 34, which have annular teeth meshing with the gear teeth 3S around the cam E, are rotatably supported on the opposite sides of the crankcase within bushings 160 held by support members 161 secured within a housing 26 formed on the crankcase. The relationship of the components supporting each gear wheel 34 in its cam guide and gear housing is best shown in FIGURE 8. The housing Z6 has a window or slot 26a opening into a reduced window 26h opening through the crankcase wall into the cam chamber 21a. T he periphery of the gear wheel extends through the window 26!) to mesh with the gear teeth on the cam. The opposite ends of the shaft 34a of the gear wheel is tted within the sleeve bearings 164) which are each supported in a support member 161. The support members 161 are secured within the window or slot 26a by the bolts 161a.

The rollers 30, each of which has an inwardly'tapered free end surface 162 extending into the crankcase engaging the cam surface 32, are each rotatably supported within a plurality of tapered needle bearing 163 held within a cage 164. An annular flange 165 of the roller engages the inward ends of the needle bearings limiting the outward movement of the roller. The cage 164 fits within a bore 166 extending ,into the crankcase and having a reduced inward section 167. A split ring 170 fitted around the outer end section 17tla of the roller 30 rotatably locks the roller with the threaded retainer 171. The roller and its related components are sealed within their housing by a threaded cap 172 screwed into the bore 166. The tapered features of the roller 30, the needle bearings 163, and the cage 164 permit the roller to effectively function under both radical and axial loads and combinations thereof in the same manner as conventional tapered roller bearings. The rollers 31 engaging the cam surface 33 are mounted in the housing 26 utilizing components which are identical in structure and function to those used and previously described for supporting the rollers 3i?.

As may be more easily understood from FIGURE 6, the cam E is confined between the rollers with the rollers 30 and 31 in the assembly F being positioned circumferentially 180 degrees from the rollers 30 and 31 in the assembly G. The rollers 3-3 are aligned coaxially on opposite sides of the cam. The common axis of the rollers intersects the axis of the cam. The rollers 31 are similarly oriented relative to the cam. The rollers are so positioned relative to the cam surfaces that irrespective of the position of the cam, its cam surfaces are each always in angagment with its respective rollers, though due to the varying angles of inclination of the cam surfaces the position of the line of Contact between each roller and its cam surface will vary as the cam moves relative to the rollers. For example, if the cammis moved in FGURE 6 in an upward direction, which would constitute clockwise movement as viewed from the right cud of the cam so that the cam wings 134 move toward the rollers 30 and 31, the contact between the cam surface 33 and the rollers 31 will move around the rollers 31 counter-clockwise as the wings 134 move into a position between the rollers with the line of contact between the cam surface 33 and the rollers 31 returning to the illustrated positions when the wings 134 are moved toward the left and upwardly until they are exactly positioned between the rollers 30 and 31. In a similar manner the point of contact between each roller and its cam surface will vary as the cam roates.

While the engine 2(3 has been illustrated and described in terms of only its cylinders, pistons, crankcase and related structure including the gears 34 through which power is transmitted from the engine, it is to be clearly understood that the engine also includes both fuel and ignition systems for the purposes of supplying both combustible fuel to the engine and the required electric energy through its spark plugs 74. Due to their conventional nature, neither the fuel nor electrical systems are illustrated or described. In two cycle engines fuel is most often drawn into the engine by the normal pressure reduction in the crankcase during the compression stroke of the piston, though the fuel may also be injected under positive pressure directly into the cylinders of the engine. Also, it will be recognized that the ignition system may receive its electrical power either from a magneto or through the use of a conventional generator and battery system.

The engine 2t) is started in a generally conventional manner by effecting reciprocation of its pistons until cornbustion of fuel within its cylinders is established. The engine may be started by means of a suitable starting system operated either by hand or by other means such as a battery powered electric motor coupled through a suitable gearing system, not shown, to one of the gears 34. Rotation of either of these gears, both of which mesh with the gear teeth 35 of the cam E rotates the cam about its longitudinal axis. Rotation of the cam causing its cam surfaces 32 and 33 to move relative to the rollers 30 and 31 forces the cam to reciprocate between one end position as illustrated in FIGURES 1 and l-A and the other end position at which the rollers are engaged with the cam surfaces at their respective 'peaks and troughs on the wings 134 of the cam at which position the piston assemblies C and D are at their extreme left positions. When the cam is rotated with suflicient speed to draw the necessary fuel into the cylinders and effect the required compression, ignition will occur starting the engine.

rlhe complete operational cycle of the engine shall be explained beginning wih the ignition of a fuel charge in the cylinder A of FIGURE l. A charge of fuel such as normally used in two cycle engines including air, gasoline, and oil is within the central tubular shaped chamber 101 of the primary piston 80. A separate charge of fuel, generally air, is within the annular chamber 71C which is defined at the head end of the piston around the annular protuberance 94 between the piston and cylinder heads when the piston has completed its compression stroke and is ready to be driven through its power stroke. The fuel charge within the central chamber 101 is ignited by a spark from the spark plug 74 with the gases burning and expanding toward the head 73 of the cylinder and radially outwardly toward the side wall of the cylinder in a mushroom fashion creating substantial turbulence within the burning fuel as the piston is driven toward the crankcase 21. As soon as the piston moves from the position` of FIGURE l so that the protuberance 94 is spaced farther from the head of the cylinder, it will be obvious, of course, that the annular chamber 71e ceases to clearly exist as a separate chamber and the spacing of the protuberance from the cylinder head permits communicatiion into the central chamber 101 of the piston where the fuel charge has been ignited and is burning.

As soon as the free end surface of the protuberance 94 moves away from the cylinder head 73 the burning fuel mixture spills outwardly around the protuberance into contact `with the change of fresh air which has been compressed by the primary piston into the annular chamber 71C. This separate charge of air provides additional oxygen for burning the fuel to effect an optimum condition of substantially complete, clean burning of the gaseous fuel charge. Also, the availability of the fresh air charge subsequent to the establishment of combustion in the fuel charge within the central piston chamber facilitates smooth burning and expansion of the fuel charge.

With the understanding of thecombustion process involving both a fuel charge within the central chamber 101 and a separate air charge within the annular chamber 71C, it will be obvious that both the fuel charge and the separate air charge must be introduced into their respective chambers in order to provide the necessary materials for the combustion process. In order to introduce fuel charges into the central and annular chambers 1 it is necessary that the primary piston move three strokes. For example, the piston must move from the position illustra'ed in FIGURE 1A outwardly to the position of FIGURE 1, return to the inward position of FIGURE 1-A and move again to the outward posiion of FIGURE 1, to obtain both fuel and air charges within the chambers 101 a'nd 71C, respectively.

Assuming the piston assembly to be in a fully retracted position as illustrated in FIGURE 1-A, the piston assembly moves outwardly toward the cylinder head with the primary piston 80 moving within the primary cylinder 22 while the secondary piston 83 moves simultaneously within the secondary cylinder 82. At the initiation of the outward stroke from the position illustrated in FIGURE l-A the rotational relationships between the cam E, the skirt of the primary piston, and the inside wall of the primary cylinder is illustrated in FIGURE 6. It is to be understood, however, that FIGURE 6` is an exploded view and in actual operation the primary piston at the inward end of its stroke is positioned with its head or outward face at the bottom or inward ends of the exhaust ports 63 and outer transfer ports 65 as illustrated by the broken line representation of the overlay of the piston surface on the cylinder Wall surface in FIGURE 6v. At this position the ports 92 in the piston skirt coincide with the generally heart shaped lower or inner transfer ports 70 while the air inlet ports 60' are covered by the piston skirt 85. The piston is inward of the upper or outer trans fer port 65 and the exhaust ports 63. As the piston moves outwardly the action of the cam surfaces 32 and 33 with the rollers 36 and 31 causes rotation of the piston which, for purposes of this description, is` considered in the direction indicated in FIGURE 6. As the piston simultaneously moves outwardly and revolves about its longitudinal axis, the piston skirt windows 92 move out of registry with the inner transfer windows 70, the piston head covers the outer transfer windows 65 and the exhaust ports 63 while the skirt of the piston along its trough sections 91d progressively uncovers the air inlet ports 60 through the cylinder Wall. The configuration of the troughs 91d and the ports 60 are such that the piston skirt and the ports cooperate to rapidly open the ports to permit maximum air intake through them. The outward movement of the primary piston effects a reduction of pressure within the intake chamber 71a around the secondary cylinder 82 so that when the piston skirt uncovers the inlet ports 60' air is drawn into the primary piston within its piston skirt. It will be seen that when the primary piston has passed the position at which it has rotated and moved outwardly sufficiently to fully uncover the inlet ports 60, the skirt will also uncover the transfer ports 7) which, however, has no effect upon the air which was drawn into the piston through the ports 60 or the gases within the combustion chamber since the outer transfer ports 65 at the other end of the air transfer ow passages 71 are covered by solid portions of the piston skirt and thus no pressure differential is effected across the ports 76 to cause ow through them.

The outward movement of the piston assembly, of course, includes the secondary piston 83 which moves outwardly farther into the secondary cylinder 82 reducing the pressure within the secondary cylinder inward of or within the secondary piston 83 so that fuel, which may include gasoline, oil and air, is drawn through the inlet flow passages 44 and the manifold 42, around the vanes 50, into the secondary cylinder 82 within the secondary piston around its rod 84. When the piston assembly has moved outwardly to the end of its stroke as represented in FIGURE l, the protuberance 94 is spaced a small distance from the head 73 of the primary cylinder while the secondary piston is moved into the secondary cylinder as also shown in FIGURE 1. The cam E along with both of the piston assemblies have rotated degrees so that the wings 134 of the cam are each between the cam rollers while the skirt of the primary piston has fully uncovered the intake ports 60 and the inner transfer ports 70 and partially uncovered the outer transfer ports 65. The uncovering of the inner and outer transfer ports does not, however, affect the charge of air drawn into the cylinder beneath the primary piston since the uncovered ports are all beneath or within the piston rings of the primary piston and no pressure differential is effected across either of the transfer ports at this stage and thus no ow of the air occurs. The piston reaches the outward end of its stroke after 90 degrees rotation and a charge of air has been drawing into the intake chamber 71a of the cylinder and a charge of fuel has been drawn into the secondary cylinder beneath the secondary piston. The piston starts returning inwardly while continuing its rotation. As the piston moves inwardly and rotates, the trough sections 91e of the piston skirt pass downwardly and across the intake ports 60 with the skirt fully covering the intake ports, the trough section 91e having substantially the same edge configuration as the top or outward edge of the inlet ports. As the piston moves farther inwardly and rotates farther the piston skirt along its trough sections 91d moves over and covers the transfer ports 7G so that they are fully covered by the time the piston head uncovers the outer transfer ports 65. As the piston moves farther inwardly and rotates farther the inlet ports 60 and the transfer ports 70 are fully covered by the piston skirt while the head end of the piston begins uncovering the ports 63 and the transfer ports 65. The inward movement of the piston raises the pressure within the chamber 71a and at substantially the time the piston skirt fully covers the ports 60 and the transfer ports 70 while beginning to uncover the transfer ports 65, the piston windows 92 begin to move into registry with the inner transfer ports 70- so that the compressed air in the chamber 71a is displaced through the piston windows 92, through the inner transfer ports 70, and into the transfer flow channels 71. The generally heart shape of the ports 70 lengthens the time period during which the windows 9- are aligned with them as windows move through a trough pattern at the bottom of the piston stroke as it reverses direction. The air flows to the outer transfer ports 65 through which it flows back into the cylinder into its combustion chamber portion. Thus, the air which was drawn into the piston during its outward stroke is cornpressed and displaced around the piston into the cornbustion chamber of the cylinder.

The inward stroke of the piston assembly also transfers the fuel charge from its position in the secondary cylinder within the secondary piston around the piston into .the annular chamber 114 of the secondary cylinder between its head 115 and the secondary piston. The secondary piston and its tubular rod 84 are secured with the primary piston rod so .that Ithe ports 121 of the secondary piston rod 84 are circumferentially coincident with the longitudinal ports in the primary piston rod and are longitudinally aligned so that the ports 121 are each substantially coincident with appnox-imately the inward half of the adjacent slots 110. The slots 110, of

course, are positioned within the sleeve 82b while the slots 121 are located around or exterior of the sleeve so that when the piston assembly is rotated to place the slots 120 of the sleeve 82b between corresponding ports 110 and 121, fluid may flow between the ports 110 and 121 throu-gh the slot 120. When the piston assembly is rotated so that the port 120 is not between the ports 110 and 121 here is no fluid communication between the ports 110 and1211.

When the piston assembly is at the outer end of its stroke, as in FIGURE l, and starts its inw-ard movement, the piston assembly is rotated by the cam E to a position which circumferentially aligns eac-h pair of ports 110 and 121 with a port 120 so that fuel within the secondary piston 83 around its piston rod 84 is displaced into the ports 121, through the ports 120, and through the slots 110 in the primary piston rod 81 into the chamber 104. Since the ports 110 of the primary piston rod extend beyond or outward of the secondarypiston 83 and its piston rod S4, the fuel Hows through the chamber 4 and 4back outwardly through the outer end sections of the slots 110 and again through the slots 120 into the secondary cylinder chamber 114 between the secondary piston and the head 115 of the secondary cylinder. The movement of the piston assembly from its outer end position of FIGURE 1 to the inward end position of FIG- URE l-A thus effects transfer of fuel into the secondary cylinder cham`ber114 between its he-ad and the secondary piston.

As the completion of this inward stroke of the piston assembly the air charge has been transferred into the combustion chamber between the head 73 and the head of the primary piston and the fuel `chargeis within the secondary cylinder chamber 114 between its head and the head ofthe secondary piston.

The piston assembly then again-starts outward movement with continued rotation which aligns each port 111 in the primary piston rod outward of the protuberance 10S` with one of the slots 120 in the sleeve 82b so that the outward movement of the secondary piston into the annular secondary cylinder chamber 114 raises the pressure in the secondary cylinder chamber forcing the fuel charge from the chamber 114 inwardly through the ports 120 and the aligned slots 111 into the central chamber 101 of the primary piston. By the time that the piston assembly is once again at the outward end of its stroke the fuel charge is transferred from the chamber 114 into the central chamber 101 where its is in position to be ignited by the spark plug. During this outward movement of the piston assembly the charge of air which was introduced into the combustion chamber portion of the cylinder through the transfer ports 65, `as previously explained, is compressed within the annular chamber 71C which is formed at the head of the piston when the primary piston is at t-he end lof its outward or compression stroke so that the air within the chamber 71a` is available to provide oxygen for the combustion process as previously discussed.

In starting the engine it will be evident that before ignition can be effected in each of its cylinders it is necessary that its pistons be reciprocated by application of power through the gea-rs 34 and the cam E until fuel and air have been introduced into the central chamber 101 of each primary piston and into the combustion chamber portion of each cylinder, as described above. Thus, in starting the engine7 assuming its pistons to be inf the positions illustrated in FIGURES 1 and 1A, and that no fuel is in cit-her of the cylinders, it is turned over by the gear wheels 34 so that `piston assembly C moves inwardly or toward the left to its inward end position while simultaneously rotation 90 degrees, and the piston assembly C then moves outwardly pulling a fuel charge into its secondary annular cylinder chamber 114 within` its secondary piston while simultaneously pulling a charge of air through the intake ports 60 into its chamber 71a. The piston assembly C then again moves toward the left while rotating a further 90 degrees by the time it again reaches the inward end of its stroke displacing the fuel charge to t-he other side of the secondary piston within the secondary cylinder and transferring the air charge from within the chamber 71a linto the combustion chamber 71b through the transfer {ports 70, the transfer ow passages 71, and the transfer yports 6'5. The piston assembly C t-hen moves outwardly again through its compression stroke during which the fuel charge is transferred from the secondary cylinder into the central chamber 101 while the primary piston compresses the air charge within the combustion chamber so that the cylinder A is ready to be fired by the sprak plug 74.

Being rigidly connected with the p-iston assembly C, the left piston assembly D also reciprocates and rotates simultaneously one stroke and degrees out of phase 'with the piston .assembly D. The left hand piston assembly D first moves from the position. of FIGURE 1-A outwardly drawing a charge :of air into the chamber 71a and .a charge of fuel into the secondary cylinder within the secondary piston, such charges being then transferred into the central chamber of the primary piston and the combustion chamber section of the primary cylinder as the piston assembly moves from its left end position back to its inward end position The next stroke of the piston assembly D is its compression stroke during which the fuel charge is transferred from within the secondary cylinder to the central chamber of primary piston while the air charge is compressed so that at the end of the compression stroke the combustion is established in the cylinder by its spark plug.

It will therefore be seen that in starting the engine from the position shown in FIGURES 1 and l-A the left hand cylinder B is the first to fire followed on the next stroke by the right hand cylinder. Each cylinder fires at the end of each outward stroke of its piston assembly. Each piston assembly rotates degrees between firings, and since the two piston assemblies are 90 degrees out of phase one of the cylinders is firing each 90 degrees of rotation of the cam and piston assemblies.

While only the necessary cycles or strokes of each piston assembly required to drawn a fuel charge and an ir charge into each of the cylinders have been described above, it will be understood that once the engine is started the process is a continuous one so that each of the opposing cylinders fires at the end of each of its outward strokes at evenly spaced alternate intervals, the right cylinder firing and moving through its power stroke while the left cylinder is moving through its compression stroke. Also,

once the engine is started, the movement of each piston assembly through its pow-er stroke simultaneously effects transfer of its next fuel charge from the inside to the outside of its secondary piston and transfer of its next air charge from within its intake chamber into its combustion chamber.

Toward the end of its power stroke each piston uncovers its exhaust ports 63, as shown in FIGURE 1-A, permitting the burned gases to be discharged from the cylinder while the next air charge is being transferred into the combustion chamber and the fuel charge into the central chamber 101 of the primary piston. Movement of fuel and air into a cylinder while discharging the burned gases is conventional procedure in two cycle engines. The fresh fuel and air charges aid in displacing the burned gases. Also, during each compression stroke a fresh charge of fuel is drawn into the secondary cylinder through the intake manifold 42 while a fresh charge of air is simultaneously drawn into the primary cylinder through the ports 60.

Upon ignition the burning fuel charge in the central chamber 101 advances from the central chamber toward the piston head 73 with a substantial pressure reduction occuring near the base or inward portion of the central chamber. The burning charge advances also radially as it is fed by the fresh oxygen from the annular space 71C. During each cycle of each piston of the engine a residue of burned gases is not scavenged from the combustion zone of each cylinder and thus remains in the central tube. This residue of burned gases acts as a buffer between a fresh charge of fuel liowing into the central chamber and the charge of oxygen-rich air in the chamber 71c. This buffer of burned gases is dispersed by the time of ignition into both the fresh fuel charge and the air charge. The momentum of the fuel advancing into the central chamber during its charging, the outward motion of the central chamber as the primary piston moves through its compression stroke, the rapid deceleration of the primary piston toward the end of its outward stroke, and the volume of the fresh fuel charge combined to insure that the spark plug is flooded with a fresh fuel charge. The pump action of the secondary piston during the transfer of the fuel charge into the central chamber accomplishes a supercharging effect.

As each piston is driven through its power stroke the cam E is moved axially urging the cam surface 32 or 33 against the pair of fixed rollers 30 or 31, depending upon which piston is firing, effecting 90 degree rotation of the cam and the pistons. For example, when the right hand piston C is driven through its power stroke the cam surface 32 is forced against the rollers 30 causing rotation of the cam and pistons. When the left piston D then moves through its power stroke the action of the rollers 31 and the cam surface 33 rotates the cam and pistons another 90 wdegrees. As the cam'is rotated by the longitudinal action of the pistons and the camming action of the rollers with its cam surfaces, the cam gear teeth 35 meshing with the gears 34 rotate the gears so that the power is delivered from the pistons through the cam and gears to any desired power transmission means, not shown, connected with the gears. Each piston stroke rotates the cam 90 degrees and each piston fires each 180 degress of cam rotation. Since the pistons fire alternately, there are four power strokes each 360 degrees of cam and piston rotation.

During the reciprocation of each of the piston assemblies, each assembly moves both longitudinally along its axes and rotationally around Stich axis without the usual lateral forces being applied to the piston rods or between the pistons and the walls of their cylinders as found in the conventional engines having a crankshaft driven by connecting rods pivotally secured with pistons.

It will now be seen that a new and improved power conversion apparatus has been illustrated and described.

It will now be seen that a new and improved engine has been illustrated and described.

It will be further seen that a new and improved internal combustion engine has been illustrated and described.

It will be additionally seen that a new and improved two cycle cam type engine has been illustrated and described.

It will be further seen that an engine embodying the invention includes opposed pistons on connecting rods extending along a common axis coincident with the longitudinal axes of the pistons and connected with and driving a centrally positioned rotary cam having cam surfaces coacting with fixed rollers to rotate the cam and pistons with their connecting rods and to transmit power from the cam through gear teeth formed around its outer surface.

It will also been seen that a cam type engine embodying the invention includes opposed cylinders aligned along a common axis and adapted to reciprocate a centrally positioned interconnected rotary cam having cam surfaces engageable with fixed rollers to effect rotational motion of the cam and the piston concurrently with their reciprocating motion to deliver power to gear means meshing with the gear teeth on the cam and to effect valving action between the rotating pistons and their fixed cylinders.

A It will also be seen that an engine embodying the invention includes opposed cylinders aligned along a common axis and connected with piston rods each having an axis coincident With the common axis of the piston and adapted to reciprocate along such common axis while rotating around the axis thereby eliminating the lateral or side forces in both the piston rods and between the pistons and their cylinder walls.

It will be further seen that one form of engine embodying the invention utilizes a localized stratified fuel charge delivered into one section of each combustion chamber while a separate air charge is delivered into another section of the combustion chamber to increase the oxygen supply for improving the combustion characteristics of the fuel in the chamber.

It will also be seen that one internal combustion engine embodying the invention has a central tubular fuel chamber in each of its primary pistons and when each of these pistons is at the end of its compression stroke a protuberance on each primary piston around the central chamber denes an annular chamber for compressing a substantially separate air charge within the combustion chamber so that the fuel charge burns radially outwardly toward the head of each cylinder providing a mushroom effect in its burning pattern with a substantial oxygen supply being available for combustion to insure smoothness and completeness of the combustion cycle.

An alternate form of an engine 200 embodying the invention is illustrated in FIGURES 5 and 5-A. The engine 200 has a plurality of components and features of components which are identical or substantially identical to those of the engine 20 of FIGURES l and l-A. For purposes of brevity, the above description of the engine 20 shall be relied upon regarding those specific details which the engine 200 shares in common with the engine 20. Identical components and features of components in FIGURES 5 and 5-A as those found in the engine 20 shall be referred to by the same reference numerals as used above and in FIGURES l and l-A. Also, components of the engine 200 which vary only in minor details from components of the engine 20 shall be referred to by the same reference numerals as used in FIGURES l and l-A with a prime mark appended thereto.

Referring to FIGURES 5 and 5-A, the engine 200 includes a crankcase or cam and bearing box 21', opposed right and left cylinders A and B with their respective piston assemblies H and I, a cam E within the crankcase interconnecting the piston assemblies, and identical gear and cam guide assemblies J and K. The piston assemblies and the cam are secured together along a common longitudinal axis with the two pistons being positioned relative to such axis in degree spaced phase relationship so that the piston and the cam reciprocate and rotate about the axis simultaneously as a unit, one piston moving through a power stroke while the other piston is in its compression and exhaust stroke. As in the case of the engine 20, the engine 200 operates on a two cycle principle with the piston assemblies H and I driving the cam in a reciprocating pattern along its longitudinal axis while the cam and the piston assemblies are rotated by coaction between the end cam surfaces 32 and 33 and the pairs of guide rollers 230 and 231 of the gear and cam guide assemblies J and K. As in the case of the engine 20 the rotation of each of the piston skirts relative to its cylinder wall of the engine 200 provides the necessary valving action for intake of fuel and exhaust of burned gases.

The right cylinder unit A includes a cylinder 22 having an external annular base flange 232 by which the cylinder is secured to an external annular ange 233 on the crankcase by a plurality of bolts 234. A base platey 235 defining the inward or base end of the cylinder is secured between the fianges 232 and 233. A sleeve 240 is formed integral with the base plate 235 for receiving and guiding a piston rod 241 of the piston assembly H. All other features of the right cylinder unit A' including the intake ports 60 and exhaust ports 63 along with the inner and Outer transfer ports 65 and 79, respectively, are identical The left cylinder assembly B is identical in all respects to the right cylinder assembly A' and is secured to the other end of the crankcase in the same manner. The planar development of the insidewall of the cylinders 22 is Shown at the left in FIGURE 6.

The piston assembly H includes a piston 250 having a head 251m, a skirt 251 provided with an irregular base end or inward edge 91, and transfer ports or windows 92, both of which are illustrated in the planar development of the piston surface at the center of FIGURE 6. The piston has piston ring grooves 93 each of which receives a piston ring 252. The piston 250 is secured on the piston rod 241 which slidably extends through the sleeve 246 and is connected along its base end 241a to the cam E in a manner to be explained hereinafter. The piston 250 is slidable within the cylinder and divides the cylinder into a variable size combustion chamber section 254 between the piston head 250a and the cylinder head 73 and a variable intake chamber section 255 between the base plate 245 and the piston. The left piston assembly I is identical in every respect to the right piston assembly and is secured along the inward end section of its piston rod to the cam E at a rotated position spaced 90 degrees around the common axis of the cam and piston assemblies from the piston assembly H to provide the proper valving action between the pistons and cylinders since the pistons are in opposite phase relationship with one of the pistons moving through its power stroke while the other is moving through its compression and exhaust stroke.

The cam E is identical in all respects to the cam E of the engine except that the earn E utilizes a single central transversely positioned web 260 in lieu of the two sets of webs 141 in the cam E for connecting the piston rods to the cam. The tapered base end section 241e of each of the piston rods 241 is received in a tapered bore 262 through a clamp member 263 connected with the cam web 260 by a plurality of bolts 264. Each piston rod base end section is held in the clamp member by a nut 265 threaded on the piston rod within its clamp 263 while the piston rod is held against rotation relative to the clamp by a key 270 inserted between the clamp member and the piston rod end section. One of the clamp members 263 has internally threaded circumferentially spaced holes 270 while the other of the clamp members 263 has corresponding smooth holes 271 so that the bolts 264 may pass through one of the clamp members and the web 260 to be threaded into the other of the clamp members 263 for holding the two clamp members on opposite sides of the web. Thus, the two pistons are held by their piston rods to the web of the cam so that the cam and the two pistons reciprocate and revolve simultaneously as a unit. An air passage 272 extends through the two clamp members and the web 260 to prevent development of a pressure differential across the web and clamp members during reciprocation of the cam within the crankcase. The crankcase 21 has at least two ports 273 open to the atmosphere.

The gear and cam guide assemblies] and K are essentially the same in construction and identical in function to the gear and cam guide assemblies F and G shown in FIGURES 1 and l-A. Thus, the gears 34 which mesh with the gear teeth 35 around the cam E are rotatably mounted on opposite sides of the crankcase as previously described. The gears 34 are connected with suitable conventional starting and power transmission apparatus, neither of which are shown, for starting the engine and for transmitting power from the ycam E through the gears to whatever means is driven by the engine.

The pairs of cam guide rollers 230 and 231 while functioning identically to the rollers 30 and 31 of the engine 20 are constructed somewhat differently andthus shall be described in detail. Each of the cam guide rollers 230 and 231 are identical in construction and thus only one of the guide rollers shall be described. The guide roller 236 is rotatably supported within a plurality of tapered roller bearings 280 which are held around the roller by an outer tubular race 281. The guide roller 230 has an intermediate reduced section 282 and a further reduced end section 283 providing an external annular outwardly facing shoulder 284. The reduced section 282 is received within an annular retainer 285 which also functions as an inner race around which a set of the tapered roller bearings 280 are held by the outer race for rotatably supporting the outer end of the guide roller. The retainer 285 has an outer end internal annular shoulder 290 which engages the shoulder 284 on the roller guide holding the guide roller against outward movement or alternatively serving as a thrust bearing opposing outward axial loads imposed on the roller by its engagement with the cam surface 32 on the cam E. The reduced end section 283 of the guide roller slidably ts through an annular retainer 291 threaded into the lcrankcase section 26 for holding the roller guide along with its bearings and related components in the crankcase housing. The retainer 291 has a plurality of circumferentially spaced axial holes 292 for lubrication and ventilation purposes.

The principle operational functions of the engine 200 are essentially identical to those of the engine 2Q with the exception, however, that the fuel intake into the engine 200 is less complex and does not involve the separate fuel and air charges used in the engine 20. The relative positioning of the intake, exhaust, and transfer ports and their relationships with the cam E are the same as previously described and illustrated in FIGURE 6. The engine 2110 functions in the same manner as a Iconventional two cycle engine insofar as its power, exhaust, intake, and compression cycles are concerned. Upon the igniting of fuel within the combustion chamber of the engine by its spark plug the piston advances through its power stroke during the latter stages of which the expanding burned gases are exhausted while a new fuel charge including gasoline, oil, and air is being introduced into the combustion lchamber of the cylinder. During the compression stroke of each piston a fresh fuel charge is drawn into the intake chamber for subsequent transfer on the next cycle into the combustion chamber. Applying this cycle sequence specifically to the engine 200, the right piston assembly H as illustrated is positioned substantially at the end of its compression and beginning of its power strokes while the left piston I is at the end of its power and beginning of its compression strokes.

The fuel intake conduits 54 of the -cylinders A and B are connected with suitable carburetion means, not shown, which permits a reduced pressure applied through the intake ports 60 to'draw a vaporized mixture of gasoline, oil, and air into each of the intake chambers 255. To start the engine it is obviously necessary that it be turned over by suitable starting mechanism connected with the gears 34 which through their engagement with the gear teeth 35 rotate the cam. Rotation of the cam causes its Icam surfaces 32 and 33 to move relative to the cam guide rollers 230 and 231 effecting longitudinal motion of the cam as it is rotated causing the pistnn assemblies H and I to be reciprocated within their respective cylinders A and B.

Assuming that the pistons are positioned as illustrated in FIGURES 5 and 5-A when the starting of the engine is initiated, a fuel charge is first drawn into the cylinder B in the following manner. Referring specifically to FIG- URE S-A, the longitudinal outward revolving movement of the piston assembly I by cam E reduces the pressure within the intake chamber 255 between the piston and the cylinder base plate 235 with the reduced pressure causing a fuel charge to be drawn into the chamber through the intake ports 60 when the intake ports are uncovered by the piston skirt as the piston moves outwardly. At the outward end of the stroke of the piston, which is at about the position shown in FIGURE 5, a fuel charge has been drawn into the intake chamber 255 and the cam and pistons have been rotated degrees.

As the piston starts returning on its inward stroke the piston is rotated so the piston skirt covers the intake ports confining the fresh fuel charge to the intake chamber 255 beneath the piston. As the piston starts its inward stroke the portion 91e of the edge of the piston skirt quickly covers the intake ports 60 while the relationship of the skirt with the transfer ports is as previously described such that no fuel flow occurs through the transfer ports or their connecting transfer passage until the proper time for transferring the fuel charge around the piston head into the combustion chamber. The piston continues its inward stroke while simultaneously rotating so that near the inward end of its stroke the transfer windows 92 move into registry Lwith the inner transfer ports 70 so that the increasing pressure within the chamber 255 due to the inward movement of the piston forces the fuel charge in the intake chamber through the transfer windows 92 and the inner transfer ports 70 into the transfer flow passages. At the time that the transfer windows 92 in the piston skirt start moving into alignment with the inner transfer ports 70 the piston 250 begins uncovering the outer transfer ports 65 so that the fuel charge being forced by the increasing pressure in the chamber 255 into the transfer fiow passages flows through the flow passages into the combustion chamber through the outer transfer ports 65. Thus, by the time the piston reaches the inward end of its strokea charge of fuel has been displaced around the piston head through the transfer ports into the combustion chamber. The piston then again begins an outward stroke compressing the fuel charge until the piston again reaches substantially the position shown in FIGURE at which time the fuel charge is ignited by the spark plug 74 starting the engine so that the burning, expanding, gases force the piston again inwardly through a power stroke during the latter stages of which the head end of the piston moves inward of the exhaust ports 63 at substantially the sarne time as the outer transfer ports are uncovered so that the burned, expanding gases are discharged through the exhaust ports 63 simultaneously with the forcing of a new fuel charge into the combustion chamber from the chamber 255. The incoming fuel charge aids in scavenging or displacing the burned expanding gases through the exhaust ports.

During the power stroke of the piston the force of the expanding gases is applied to the piston and transmitted through the piston rod to the web 260 of the cam E' causing the cam to be moved longitudinally within the crankcase 21, When the left piston I is being driven through its power stroke the cam is displaced within the crankcase toward the right by the piston rod. The force applied toward the right on the cam causes the cam surface 33 to be pressed against the guide rollers 231 so that the cam is caused to rotate as the cam moves toward the right relative to the guide rollers. During the movement of the piston from its outward end position to its inward end position it again is rotated through 90 degrees so that the intake ports 63 are covered by the skirt of the piston while the transfer window of the piston is again aligned with the inner transfer ports in the cylinder wall so that another charge of fuel is forced through the inner and outer transfer ports and the transfer ow passages into the combustion chamber while the previously ignited and expanding gases are being exhausted through the exhaust ports. The right hand piston H functions in an identical manner one cycle out of phase with the left hand piston so that they fire in alternating sequence with the right hand piston moving through its power stroke while the left hand piston is moving through its compression stroke, one of the cylinders firing each 90 degrees rotation of the cam E. Thus, each piston draws fuel into the chamber 255 during each of its outward strokes while compressing the fuel charge in its combustion chamber and during the immediately following power stroke the fuel charge in the chamber 255 is somewhat compressed and at the end of the power stroke transferred through the transfer ports into the combustion chamber while the expanding burned gases are exhausting through the exhaust ports. The configuration of the piston skirts and the positioning of the transfer windows relative to the ports provided in the cylinder wall provide the desired valve action for fuel intake and transfer of the fuel charges into the combustion chamber as the pistons rotate during their reciprocation.

The rotating cam E by its teeth 35 meshing with the gear wheels 34 causes the gear wheels to be driven about their respective axes of rotation. Power is transmitted from the engine by suitable transmission means, not shown, connected with the gear wheels.

It will now be seen that in a modied form of internal combustion engine embodying the invention a contoured piston skirt having transfer fuel windows therein is simultaneously reciprocated and rotated through predetermined positions relative to transfer ports in the cylinder walls of the surrounding piston for performing fuel intake and transfer functions.

It will be further seen that the piston rods are connected with a common webbing within a centrally positioned longitudinally and rotatably movable cam adapted to coact with iixed rollers for rotating the cam and pistons simultaneously with longitudinal motion of such cam and pistons.

It will also be seen that in the modified form of the invention the engine has pistons dividing each cylinder into a fuel intake chamber and a combustion chamber and each cylinder and piston has ports which are sequentially aligned upon reciprocating rotational motion of the piston to draw fuel into the intake chamber, transfer the fuel into the combustion chamber, and exhaust burned gases from the combustion chamber while transferring fuel from the intake into the combustion chamber.

It will be recognized that variations may be made in the various operational steps of both the engines 20 and 20) by altering the size, shape, and positions of the intake, exhaust, and transfer ports along with the shape of the piston skirts. In the operation of the engines the timing or tiring point may be altered. Also the cam surfaces of the cams F and F may be altered to change the relationship between the reciprocation and rotation of the cam and piston. For example, port and cam changes may be ma-de to increase the number of times each cylinder fires for each complete rotation of the cam. Further, power transfer from the cam of the engines may be effected by such other means as a frictional drive, a spline structure interconnected with the cam, electrical means, or a hydraulic power transfer system.

It will also be recognized that in place of the air cooling tins 71 and 72 on cach cylinder the cylinders may be provided with double walls or jackets connected with a radiator, not shown, for uid cooling of the engine.

The foregoing description of the invention is explanatory only, and changes in the details of the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed and desired to 'be secured by Letters Patent is:

1. An engine comprising: crankcase means; a plurality of cylinder means supported on said crankcase means; piston means movably supported in each of said cylinder means; means providing a central chamber in each of said piston means having restricted communication with the combustion chamber within said cylinder means; means for introducing one fuel charge into said central chamber independently of said combustion chamber; means for introducing another fuel charge into said combustion chamber independently of said central chamber; and means within said crankcase means interconnecting said piston means whereby said piston means are reciprocatable along and rotatable about a common axis.

2. An engine as dened in claim 1 wherein said means interconnecting said piston means has cam surfaces, and

including means connected with said `crankcase means adapted to coact with said cam surfaces for guiding said means interconnecting said piston means through a reciprocatin g rotating pattern.

3. An engine as defined in claim 2 including gear means operatively associated with said crankcase means and with said means interconnecting said piston means and adapted to rotate and be rotated by said means interconnecting said pistons while said means moves axially and rotatably.

4. An engine as defined in claim 1 wherein said cylinder means and said piston means are each provided with ports adapted to be selectively aligned responsive to combined axial and rotational motion of `said piston means for admitting fuel into said cylinder means and discharging exhaust fiuid from said cylinder means.

5. An internal combustion engine comprising: crankcase means; cylinder body means supported on said crankcase means providing opposing coaxial cylinder chambers; piston means slidably positioned in each of said cylinder chambers; cam means sup-ported in said' crankcase means connected between said piston means whereby said cam means and said piston means are movable as a unit; guide means supported by said cranlrcase means engageable with said cam means for guiding said cam means through a reciprocating rotating pattern; each said cylinder body means and said piston means providing separate fuel charge and air charge containing means on intake and combustion sides of said piston means; and means provided by said cylinder body means and said piston means for controlling fuel and air charge intake into said separate containing means, transfer of said charges to said separate containing means on said combustion side of said piston means, maintaining said charges separate until ignition, and discharge of exhaust gases from said combustion side of said piston means responsive to combined reciprocating rotating motion of each of said piston means.

6. An internal combustion engine comprising: a crankcase housing; a first cylinder body having a first cylinder chamber secured to said crankcase housing; a second cylinder body having a second cylinder chamber secured to said crankcase housing on an opposite end of said housing; said first and second cylinder chambers having coincident axes; a first piston assembly slidably positioned in said first cylinder chamber; a second piston assembly slidably positioned in said second cylinder chamber; said first and second piston assemblies having coincident axes; each of said piston assemblies including a primary piston dividing its cylinder chamber into variable size combustion and intake chambers each said cylinder body and said primary piston providing separate fuel charge and air charge containing means on intake and combustion sides of said primary piston; means provided by said cylinder body in said primary piston for controlling fuel and air charge intake into said separate containing means, a transfer of said charges to said separate containing means on the said combustion side of said primary piston, maintaining said charges separate until ignition; a cam positioned for longitudinal and rotational movement Within said crankcase housing interconnected between said piston assemblies, the axis of said cam being coincident with the axes of said piston assemblies; fixed guide means supported by said crankcase housing and engageable with said cam for guiding said cam through a rotating reciprocating pattern whereby said cam and said piston assemblies are rotated as a unit about their axes as they reciprocate along said axes; each of said cylinder members having an intake port opening into its intake chamber, an exhaust port opening into its combustion chamber, and transfer port and flow passage means connecting its intake chamber with its combustion chamber; and each primary piston having a skirt section slidable along the inner Wall of its cylinder body, said skirt having a contoured base end edge and @transfer window, the

position of said transfer window and configuration of said skirt edge being correlated with said intake port opening and said transfer port and fiow passage means of its cylinder body to control fuel intake and transfer into its combustion chamber responsive to rotating reciprocating movement of said piston assembly.

7. An internal combustion engine as defined in claim 6 wherein each of said piston asesmblies includes means providing a central fuel charge chamber in said primary piston in communication with its combustion chamber, means for introducing one portion of a fuel charge into said central chamber independently of said combustion chamber, and means for introducing another portion of a fuel charge into said combustion chamber independently of said fuel charge portion in said central chamber, said portions of said charges being brought together in said combustion chamber upon ignition of said fuel charge in said central chamber.

8. An internal combustion engine as dened in claim 6 wherein each of said piston assemblies' is provided with a central chamber extending through the primary piston thereof for receiving a first fuel charge portion, said central chamber being in communication with said combustion chamber, and said piston assembly being further provided with means providing an annular chamber around said central chamber for receiving a second fuel charge portion, said piston assembly and its cyiinder body having means for transferring said second fuel charge portion into said combustion chamber independently of said first fuel charge, said combustion chamber being formed to permit mixing of said first and second fuel charge portions in said combustion chamber upon ignition of one of said charge portions.

9. An internal combustio-n engine as defined in claim 6 wherein each of said piston assemblies includes means providing a central fuel chamber communicatable with said combustion chamber of the cylinder in which said piston assembly is slidable, intermediate chamber means for receiving a fuel charge preliminary to transfer of said fuel charge into said central chamber, means providing a fuel chamber separate from said central fuel chamber and intermediate chamber means adapted to receive a separate fuel charge for transfer into said combustion chamber independently of said first fuel charge, and means separating said fuel charges until ignition.

1t). An internal combustion engine as defined in claim 6 wherein each primary piston has a central fuel chamber communicatable with said combustion chamber; means in each cylinder body defining within its cylinder chamber an internal annular air intake section; each of said cylinder bodies includes means providing a secondary annular cylinder concentric within said ail` intake section; a fuel intake manifold connected with each of said cylinder bodies in communication with said secondary annular cylinder; each said piston assembly including a piston rod slidable through said secondary annular cylinder in each of said cylinder members; each said piston assembly including a secondary annular piston secured with said piston rod and adapted to reciprocate within said secondary annular cylinder; said piston assemblies each having ports for transferring a fuel charge from its fuel intake manifold through the said secondary annular cylinder around its piston rod into its central fuel chamber responsive to longitudinal and rotational motion of each said piston assembly relative to its cylinder body, each said air intake section being communicatable with the transfer port and flow passage means associated therewith for transfer of an air charge into said combustion chamber independently of said fuel charge in said central chamber responsive to longitudinal reciprocating motion of each said piston assembly, and each of said rst and second piston assemblies having means for maintaining said air and fuel charges separate until ignition.

1l. An internal combustion engine comprising: a crankcase housing; fuel intake manifold means secured on said crankcase housing; cylinder assembly means secured to said crankcase housing, said cylinder assembly means having coaxial primary cylinder chambers; each said cylinder assembly including a secondary cylinder member providing an annular secondary cylinder chamber within an inner section of said primary cylinder chamber, said secondary cylinder -chamber being in communication at the base end thereof with said fuel intake manifold means; said secondary cylinder member being concentric with and spaced apart within said primary cylinder member to provide an annular air intake space around said secondary member within said primary cylinder member; a primary piston movably positioned in each of said primary cylindrical chambers; a primary piston rod secured with each of said primary pistons through said secondary cylinder member, said primary piston rod being tubular along an outer end section thereof dening a central fuel chamber within said primary piston open through the outer end of said primary piston into a combustion chamber Sectio-n of said primary cylinder chamber dened between the heads of said primary piston and said primary cylinder; a secondary annular piston on a secondary tubular piston rod secured at the 4base end thereof with the base end of said primary piston rod and telescopically iitted over a section of said primary piston rod, said secondary annular piston being movable in said secondary annular cylinder chamber coincident with longitudinal rotational motion of said primary piston; each of said primary cylinder members having air intake means opening into said annular air intake space, exhaust port means opening into said combustion chamber portion of said primary cylinder chamber, inner air transfer ports opening into said air intake space, outer air transfer ports opening into said combustion chamber, and an `air transfer flow passage connecting between said inner and outer air transfer ports; each of said primary pistons having an inwardly extending skirt slidable along the wall of said primary cylindrical chamber, each of said skirts having a contoured inward end edge surface and having a transfer port therein adapted to be aligned with said inner air transfer port for permitting displacement of an air charge from within said piston skirt within said air intake space into said combustion chamber through said transfer ports and ilow passage; said primary piston rod, said secondary piston rod, and said secondary cylinder member having ports adapted to be aligned upon longitudinal rotational motion of said primary and secondary pistons and rods for drawing a fuel charge into said secondary cylinder chamber on the inside of said secondary piston upon outward movement of said secondary piston, transferring said fuel charge around said secondary piston into said secondary cylinder chamber outward of said secondary piston upon inward movement of said secondary piston, and displacement of said fuel charge into said central chamber of said primary piston upon subsequent outward movement of said secondary piston; each of said piston assemblies being connected at the inward end thereof to a cam positioned within said crankcase housing adapted to rotate and reciprocate along an axis common with the axis of said piston assemblies and said primary cylinder chambers,

said cam having end cam surfaces for rotating said cam responsive to axial movement of said cam; cam roller guide means rotatably supported by said crankcase housing and engageable with said cam surfaces of said cam for rotating said cam responsive to reciprocating axial movement of said cam coincident with reciprocating movement of said piston assemblies, said piston assemblies being secured with said cam in spaced phase relationship whereby one of said primary pistons is moving through a power stroke while the other of said primary pistons is moving through a compression stroke; said cam having external annular gear teeth means; and gear means rotatably supported by said crankcase housing meshing with said gear teeth means on said cam for rotatably interconnecting said cam and said gear means.

12. An internal combustio-n engine as defined in claim 11, wherein each said primary piston has an outwardly extending annular protuberance on the head end thereof around said central fuel chamber for defining an annular chamber within each of said combustion chambers for containing an air charge separate from a fuel charge within said central chamber of said primary piston when said primary piston is at the outward end of its stroke.

13. An engine as defined in claim 11, wherein said cam comprises a tubular body having axially extending wing sections alternating between opposite ends of said body and equally spaced around said body, said cam surfaces eachcomprising a continuous end edge surface along adjacent cam wing sections at each opposite end of said cam.

14. An internal combustion engine having crankcase means, cylinder body means supported on the crankcase means providing opposing coaxial cylinder chambers, piston means slidably positioned in each of the cylinder chambers, means interconnecting said piston means whereby said piston means are movable as a unit through a reciprocating rotating pattern, said engine including: means providing a central chamber in said piston means having restricted communication with a combustion chamber in said cylinder chambers; means for introducing fuel into said central chamber independently of said combustion chamber; and means for introducing an air charge into said combustion chamber independently of said central chamber.

15. An engine of the character described in claim 14 wherein a vaporized fuel charge is introduced into said central chamber and including means whereby said fuel charge in said central chamber is mixed with an air charge in said combustion chamber upon ignition.

References Cited UNITED STATES PATENTS 1,527,166 2/1925 Bezu 123-73 1,666,295 4/1928 Marvin 123-47 2,352,396 6/1944 Maltby 123-45 X 3,079,901 3/1963 Hallberg 123-32 3,244,159 4/1966 Meurer 123-32 WENDELL E. BURNS, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,381,671 May 7 ,'igies T H Duff It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as' shown below:

Column 4, lines 45 and 46, "ing a tubular piston rod 84 which telescopically slides over ondary piston 83 fitting in the secondary cylinder and hav" should read ondary piston 8e3 fitting in the secondary cylinder and having a tubular -p'iston rod 84 which telescopcally slides over Signed ,and sealed this 23rd day of December 1969.

(SEAL) Edward M. Fletcher, Jvr.

WILLIAM E. SCHUYLERL JR. Attesting Officer Commissioner ofgtents 

